...if you're selling soap.
Imagine the following. You're Apple's ad agency, and you've been hired by the Reds, the local sports team. A few miles away is the home of the Blues, and in your town, the Reds make up the team affiliation of about 80% of the population, with the Blues making up the other 20%. There's a degree of rivalry between the teams.
The Reds want more people coming to their stadiums. They need increased revenue ticket sales. The only people to attract now are the Blues. The Blues obviously like your sport, otherwise they wouldn't have chosen a team in the first place, but they're not willing to consider, as yet, seeing Red team games. How do you attract Blue supporters?
If you're Apple's ad agency, your ad goes something like:
Blue: "I'm a blue player"
Red: "And I'm a red player"
Blue: "Duh. I can kick this ball, duh, look" (*kicks at ball several times, finally actually hitting it the 7th time*)
Red: *smugly bounces a ball on knee* "Red scored the highest last season, and we're consistantly the best team"
Blue: "Hey! Hey, watch this" *attempts to balance ball on nose, ball consistantly rolling off and away. Blue chases after ball*
Red: *Kicks ball up, bounces on knee, headbutts it, and catches it with one hand behind him* "We have some really skilled players"
(Ad continues ad-nausium. By which I mean it's an ad that makes you nauseous.)
Now, another approach might be to run an ad that consists of a bunch of shots from your stadium. You show some pretty good playing, stuff people will find impressive and will have wished they saw. You show the Reds most often, but, hey, there are two teams in every game. In other words, instead of taking sides based upon the team, you show people that if they come to your stadium, they're going to have a good time. They're going to see some impressive playmanship. Even if it's not their team, there's reason for them to want to go and see the next game.
Which type of ad would sway you? Which type of ad would get you to go to a stadium owned by your team's rival?
The current "I'm a Mac" series doesn't work because it appeals to fanboism, but in doing so, it also ends up being fanboism's victim. It doesn't appeal to PC owners, it just cements existing Mac user's sense of superiority. Except me. I cringe every time I see them.